1 /* 2 * Copyright 2019 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkSharingProc_DEFINED 9 #define SkSharingProc_DEFINED 10 11 #include <unordered_map> 12 #include <vector> 13 14 #include "include/core/SkData.h" 15 #include "include/core/SkImage.h" 16 #include "include/core/SkSerialProcs.h" 17 #include "src/core/SkTHash.h" 18 19 /** 20 * This serial proc serializes each image it encounters only once, using their uniqueId as the 21 * property for sameness. 22 * 23 * It's most basic usage involves setting your imageProc to SkSharingSerialContext::serializeImage 24 * and creating an SkSharingSerialContext in an appropriate scope to outlive all the images that 25 * will be encountered before serialization. 26 * 27 * Optionally, collectNonTextureImagesFromPicture can be called with an SkSharingContext and an 28 * SkPicture that may reference not-yet-released texture backed images. It will make non-texture 29 * copies if necessary and store them in the context. If present, they will be used in the 30 * final serialization. 31 * 32 * This is intended to be used on Android with MultiPictureDocument's onEndPage parameter, in a 33 * lambda that captures the context, because MPD cannot make assumptions about the type of proc it 34 * receives and clients (Chrome) build MPD without this source file. 35 */ 36 37 struct SkSharingSerialContext { 38 // --- Data and and function for optional texture collection pass --- // 39 40 // A map from uniqueID of images referenced by commands to non-texture images 41 // collected at the end of each frame. 42 skia_private::THashMap<uint32_t, sk_sp<SkImage>> fNonTexMap; 43 44 // Collects any non-texture images referenced by the picture and stores non-texture copies 45 // in the fNonTexMap of the provided SkSharingContext 46 static void collectNonTextureImagesFromPicture( 47 const SkPicture* pic, SkSharingSerialContext* sharingCtx); 48 49 50 // --- Data and serialization function for regular use --- // 51 52 // A map from the ids from SkImage::uniqueID() to ids used within the file 53 // The keys are ids of original images, not of non-texture copies 54 skia_private::THashMap<uint32_t, int> fImageMap; 55 56 // A serial proc that shares images between subpictures 57 // To use this, create an instance of SkSerialProcs and populate it this way. 58 // The client must retain ownership of the context. 59 // auto ctx = std::make_unique<SkSharingSerialContext>() 60 // SkSerialProcs procs; 61 // procs.fImageProc = SkSharingSerialContext::serializeImage; 62 // procs.fImageCtx = ctx.get(); 63 static sk_sp<SkData> serializeImage(SkImage* img, void* ctx); 64 }; 65 66 struct SkSharingDeserialContext { 67 // a list of unique images in the order they were encountered in the file 68 // Subsequent occurrences of an image refer to it by it's index in this list. 69 std::vector<sk_sp<SkImage>> fImages; 70 71 // A deserial proc that can interpret id's in place of images as references to previous images. 72 // Can also deserialize a SKP where all images are inlined (it's backwards compatible) 73 static sk_sp<SkImage> deserializeImage(const void* data, size_t length, void* ctx); 74 }; 75 76 #endif 77